Non-metallic belt-driven crosshead drive system for hydraulic decoking

ABSTRACT

An apparatus for raising and lowering a cutting tool within a decoking drum, a decoking system and a method of raising and lowering a decoking system cutting tool. Instead of using metallic ropes, chains, or a self-propelled gear-based approach, non-metallic belts are secured at respective ends to a crosshead and one or more counterweights to enable vertical movement of the crosshead that in turn permits vertical movement of the cutting tool throughout the height of the drum. A motorized pulley system controls the movement of the belt, and preferably avoids having the motor be carried by the crosshead. The belts on each pulley are preferably arranged as cooperative sets so that within each set, both primary load belts and secondary load belts are present. Enhanced engagement between at least the primary load belts and the pulleys promotes greater load-bearing capability, while the secondary load belts are sufficiently strong to ensure positional stability of the crosshead and decoking tool upon damage to or failure of one or more of the primary load belts.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application Ser.No. 62/059,406 (DUR 1093 MA) filed Oct. 3, 2014.

BACKGROUND OF THE INVENTION

This invention relates generally to devices for carrying a cutting anddrilling tool and other components for use in delayed coking reactoroperation, and more particularly to the use of non-metallic belts thatprovide a fail-safe lifting design for raising and lowering suchcomponents.

In conventional petroleum refining operations, crude oil is processedinto gasoline, diesel fuel, kerosene, lubricants or other usefulmaterials through distillation or related means. In such an operation,the crude oil (which is typically subjected to various upstreamprocessing or production steps at or near the well from which the oil isextracted) is heated to elevated temperatures in a fractionaldistillation unit in order to selectively release—depending on differingboiling points—the valuable volatile hydrocarbon components containedtherein. The heavy remaining oils are drained from the fractionationunit, heated, and transferred into vessels (known as coke drums) at atemperature (specifically, a thermal cracking temperature) sufficient todrive off the remaining volatile materials to leave the drums full ofsolid coke. Because large-scale refineries can produce as much as 2,000to 3,000 tons per day of solidified coke, the drums—which are as largeas 30 feet in diameter and 140 feet in height—must be frequently clearedto make room for the next incoming batch.

One method of breaking up the coke residue is by using a decoking (orcoke cutting) tool in conjunction with a decoking fluid, such as highpressure water. The tool (which is typically secured to a tower that isin turn mounted onto a support structure that surrounds the coke drum)is lowered into the coke drum through an opening in its top, and thehigh pressure water supply is introduced into the tool so that it can beselectively routed through—depending on the mode of operation—either thedrilling or cutting nozzles of the tool to impinge on the coke in thedrum and act as a coke-breaking fluid jet. Such tools require high flowrates and pressures (for example, flows of 1000 gallons per minute (gpm)at 3000 to 4000 pounds per square inch (psi) or more). Moreover, thetower, tool and its ancillary equipment (including among others drillstems, drive mechanisms, water-filled hoses or related conduit,collectively referred to as a cutting train that can be supported by acrosshead) can be extremely heavy, weighing (depending on the size andconfiguration) up to 15,000 pounds or more. A steel cable operated by awinch is used to raise or lower the cutting train. In addition, separatefall arresting gear is required in numerous decoking tool crossheaddesigns to prevent a freefall in the event of a cable break or a winchfailure within the tower; such redundancy adds significantly to themaintenance and operation complexity, as well as the weight and cost ofthe decoking system without contributing to the efficiency of the actualdecoking process.

To avoid having complex support structures for movement of the water jetcutting head and related equipment through the vertical entirety of thecoke drums, a self-climbing crosshead-based lifting configuration may beemployed, an example of which is depicted in U.S. Pat. No. 6,050,277(the '277 patent) that is owned by the Assignee of the present inventionand incorporated herein by reference in its entirety; such aconfiguration forms a crosshead drive system. An additional way thatredundancy and complexity is avoided in the '277 patent is through theuse of rollable carriages (such as those depicted in FIG. 3B thereof) ona track or rail so that a single tower (rather than multiple towers)that is used to support the cutting train can be transported betweenadjacent drums.

Despite the improvements made by such a configuration, difficultiesremain. For example, the long lengths of the rack-and-pinionconfiguration must still rely upon rigid support by a vertical memberthat—while not as cumbersome as a complete tower—must be robust enoughto ensure that precise engagement of their meshing gear teeth of theself-propelled drive system is maintained, as misregistration betweenthem can lead to faulty (or no) crosshead movement; such rigidity canexact significant weight, cost and complexity tolls. Moreover, if ametallic wire cable (also called rope) is used to couple the cuttingtrain to a set of counterweights over a corresponding set of pulleys inan attempt to permit the use of a smaller motor, significant additionalweight (often 5000 to 8000 pounds or more) may be present.

SUMMARY OF THE INVENTION

According to one aspect of the present invention, an apparatus formoving a cutting tool within a decoking drum is disclosed. The apparatusincludes one or more rigid members extending above the decoking drum asufficient height to permit a range of vertical movement of the cuttingtool throughout a substantial majority of the drum. A crosshead drivesystem is made to facilitate vertical movement of the crosshead may takeplace relative to the rigid member or members. The crosshead may be madeto carry the tool (such as through a fixed or rotatable drill stem orthe like), and itself may be raised or lowered within the rigid memberby a motorized set of pulleys and belts where the motor and the pulleysare not mounted on the crosshead; in this way, the weight of thevertically-movable components is significantly reduced. Substantiallyopposing ends of the belts define connection or securing points; thus,one end of each of the belts is secured to the crosshead, while theopposing end is secured to counterweight that can be made to movevertically within or adjacent the rigid member along a travel path thatis substantially parallel to the travel direction of the crosshead. In apreferred form the belts and pulleys cooperate such that one or moreprimary load belts and one or more secondary load belts can be made totravel within corresponding side-by-side channels that are formed in thepulleys; the secondary load belts may be used in the event one or moreof the primary load belts suffers a cut or related damage that impairsits ability to raise and lower the crosshead.

According to another aspect of the invention, a decoking assembly isdisclosed. The assembly includes a decoking tool configured to receive acutting fluid from a high pressure fluid source; and an apparatuscoupled to the decoking tool for moving it within a decoking drum. Theapparatus includes one or more rigid members and crosshead drive systemsimilar to that of the previous aspect.

According to yet another aspect of the invention, a method of operatingcomponents within a decoking system is disclosed. The method includesarranging an assembly to be adjacent a decoking drum and using amotorized pulley system that is part of the assembly to selectivelyraise and lower at least a crosshead and coke cutting tool that mayreceive a cutting fluid from a high pressure fluid source. As with theprevious aspects, numerous non-metallic belts engage each pulley so thatrotating the pulley causes movement of the crosshead and a counterweightaffixed to opposite ends of each set of belts. As before, at least themotor is statically mounted so that it doesn't have to raise and loweralong the crosshead and the coke cutting tool.

BRIEF DESCRIPTION OF THE DRAWINGS

The following detailed description of the present invention can be bestunderstood when read in conjunction with the following drawings, wherelike structure is indicated with like reference numerals and in which:

FIG. 1 shows a view of two-drum decoking system which can be retrofittedto use the crosshead drive system of the present invention;

FIG. 2 shows a detailed representation of a crosshead drive systemaccording to the prior art;

FIGS. 3A through 3D show various detailed views of the crosshead drivesystem according to one aspect of the present invention;

FIGS. 4A through 4C show a simplified view of the cooperation of a beltand pulley according to one aspect of the present invention; and

FIG. 5 shows a notional configuration of a toothed pulley and acomplementary-shaped belt according to another aspect of the presentinvention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring first to FIG. 1, a decoking system 1 includes a pair of cokedrums 5, a cutting and boring (also called a decoking) tool 10, a drillstem 15, a pair of towers 20, a flexible water supply hose 25 and arotary joint 30. The drum 5 on the left shows a partial cutaway that isfull of coke 7 that needs to be removed, while the drum 5 on the rightshows the decoking tool 10 being lowered through the coke 7 duringboring of a pilot hole 9. The decoking tool 10 is mounted at the lowerend of the drill stem 15 such that both can move translationally(specifically, vertically) along the length of drum 5. The upper end ofdrill stem 15 is coupled to the rotary joint in such a way that thedecoking tool 10 and drill stem 15 can rotate about a longitudinal axisformed by both. The flexible water supply hose 25 is also coupled to therotary joint 30 and is used to supply high pressure water to thedecoking tool 10. While the decoking tool 10 is mentioned as a singledevice, it will be appreciated by those skilled in the art that suchfunctions may be separated, as a separate tool that provides boring anda separate tool for cutting may be employed. The construction of therotary joint 30 is such that it acts as the intermediary between theflexible, yet non-rotational water supply coming from the flexible watersupply hose 25 and the rigid, yet rotational drill stem 15 and thedecoking tool 10. Each tower 20 acts as a hoist to lift and lower arespective one of the decoking tools 10, drill stems 15, flexible watersupply hoses 25 and rotary joints 30.

Drill stem 15 and towers 20 extend vertically above a cage-like supportstructure 40 that surrounds the drums 5, where in one form the towers 20may be mounted onto a floor-like upper deck (also referred to as acutting deck) 45 of the support structure 40 Likewise, the top of thetowers 20 and a framework 35 may form a derrick that provides supportfor the decoking tool 10, drill stem 15, water supply hose 25 and rotaryjoint 30. As can be seen, the height of each drill stem 15 and its tower20 is at least as much as the length of the drums 5 to permit drill stemtraversal along a substantial entirety of the volume of coke 7 containedtherein. As will be discussed in more detail below, the crosshead drivesystem according to one or more embodiments of the present invention maybe placed at or near the top of the tower 20. As mentioned above, thetwo-tower 20 system of FIG. 1 may also be retrofitted (not presentlyshown) to use only one horizontally moving tower 20 that can be shuttledback-and-forth between the two drums 5. In such configuration, a singletower 20 may be mounted to a mobile transport in the form of a wheeledcarriage that is situated on upper deck 45 of the support structure 40above the coking drums 5. In one form, the transport may beself-propelled (such as by a motor (not shown)), while in another, itcan be guided by a winch or related towing mechanism (not shown) withcables. In a more particular version, the transport may be mounted onrails or tracks that in one form may resemble those used to carrytrains. In this way, a single movable decoking tower 20 may be used tooperate on multiples drums 5. The crosshead drive system 200 of thepresent invention can be retrofitted onto existing decoking tool system1 in order to reduce overall system 1 complexity and redundancy.

Referring next to FIG. 2, a decoking tool carrier with a crosshead drivesystem 100 according to the prior art is shown. The system 100 includesa self-propelled rigid crosshead 110 rigid with a motor 120 mountedthereon and a reduction gearbox (not shown) having a worm gear (notshown) drivably engaged with the output shaft of the motor 120. The wormgear has output shafts 130, each defining a pinion 135 at its respectiveend. The output shafts 130 are rotatably supported in bearing blocks 140to promote secure connection between the pinions 135 and the crosshead110. The rotary joint 30 is mounted below the crosshead 110 between apair of vertically-upstanding members 145 that can be used in place ofor as part of the tower 20 of FIG. 1. Two vertical toothed racks 150,one secured to each respective vertically-upstanding member 145,cooperate with the pinions 135 such that rotation of the pinions 135under the influence of motor 120 causes the crosshead 110 to climb or todescend on the toothed racks 150. The pinions 135 are kept in engagementwith the racks 150 by means of wheels (not shown) that are mounted onaxles (not shown) to bear against the rear surfaces of the racks 150 ina clamping-like relationship. Two cables 155 are attached to the topsurface of the crosshead 110 and extend upward over pulleys 160 andthence downward to counterweights 165 which are preferably made totravel within a generally vertical path defined by the construction ofthe vertically-upstanding members 145 (which in one form may be madefrom pipes or the like).

Referring next to FIGS. 3A through 3D and 4A through 4C, the crossheaddrive system 200 according to one or more embodiments of the presentinvention is shown. System 200 includes (among other components, asdiscussed below) a crosshead 210 and motor 220. In one form, therotational speed of the motor 220—which may be electrically-powered—maybe controlled by a conventional device, such as a variable frequencydrive (VFD—not shown). Preferably, the motor 220 and gearbox 224combination limits the linear raising and lowering speeds of thecrosshead 210 to no more than about 41 feet per minute. In addition, themotor 220 can be operated remotely to minimize exposure of an operatorto the decoking operation, while in another form, the entire system maybe automated. Unlike the self-climbing system 100 of the prior art,motor 220 is statically mounted onto a rigid member deck (such asframework 235 (only the bottom portion of which is shown) that issimilar to framework 35 of the towers 20 shown in FIG. 1 that permits asecure mount for the motor 220 (as well as the pulleys that will bediscussed in more detail below); this decoupling of the motor 220 fromthe crosshead 210 means that the crosshead 210 carries less weight,which in turn can permit a less robust rigid member to act as acrosshead 210 support structure. Instead, the crosshead 210 isresponsive to movement of belts 255 that are cooperative with therotation of the output shaft 222 of the motor 220. Referring withparticularity to FIG. 3B, in one form, the rotational movement of theoutput shaft may be imparted through a dual output gearbox 224 topromote equal (but opposite) rotational movement to the belts 255through pulleys 260 that are mounted onto the framework 235 in a mannergenerally similar to that of motor 220. The pulleys 260, by virtue oftheir rotational coupling to the motor 220, impart movement to the belts255. As before, the rotary joint 30 is mounted below the crosshead 210.Instead of vertical toothed racks 150, pinions 135 and cables 155 of theprior art, the belts 255 driven by pulleys 260 raise or lower thecutting train. The pulleys 260 can be driven by motor 220 and gearbox224 combination, synchronized motors, or similar apparatus. The belts255 are secured at one end to the crosshead 210 and to the other end tocounterweights 265 that in one form can be made to travel within agenerally vertical path defined by the upstanding member 245 portions ofthe support structure in a manner generally similar to that depicted inFIG. 2. In the present context, the secured nature of the connection maybe through any conventional means so long as slippage or inadvertentrelease is avoided. As such, the belts 255 do not replace the toothedrack 150 of the prior art of FIG. 1, but rather replace the cables 155.Instead, it is the toothed features of the pulley 260 and belt 255arrangement of the present invention working together that replaces therack and pinion arrangement of FIG. 1. In FIG. 3B, the pulley 260 isshown in notional form in a single channel width configuration; as willbe discussed below in more detail in conjunction with FIGS. 3C, 3D and4C, the pulley 260 may in fact comprise multiple channels across itswidth, and may or may not include teeth to help engagecomplementary-shaped teeth in the belts 255. As such, the motor 220,gearbox 224, belts 255, pulleys 260, counterweights 265 cooperate todefine a motorized system that can selectively raise and lower thecrosshead 210.

In one form, the motor 220, belts 255, pulleys 260 and counterweights265 (as well as other components as discussed herein) may define amotorized pulley system that is part of the crosshead drive system 200.Details of augmented forms of engagement between the belts 255 andpulleys 260 is shown with particularity in FIG. 4A, wherecomplementary-shaped teeth 256 and 261 are formed on the belts 255 andpulleys 260, respectively in order to facilitate a meshed cooperationbetween them upon pulley 260 rotation. Furthermore, although thecrosshead 210 and its ancillary equipment are shown in FIG. 3A as beingsituated between two upstanding member 245 portions of the supportstructure that acts as the towers 20 of FIG. 1, it will be appreciatedby those skilled in the art that it may also be supported by a singletower or derrick in order to facilitate an even more lightweight (andmoveable) structure that can be shuttled back-and-forth between adjacentdecoking drums. In one such form, such a single-tower structure may bemoved by rollers, wheels or the like across a planar surface (such asupper deck 45 of the decoking system 1 of FIG. 1); either embodiment isdeemed to be within the scope of the present invention.

Referring with particularity to FIGS. 3C and 3D (both of which show acutaway view along Section A-A of FIG. 3A of one of the pulleys 260 tohighlight how multiple channels may define the engagement region of thepulley 260 and belt 255) as well as FIG. 4C, in one embodiment, the useof pulley 260 may be configured to include teeth 261 in one or more ofthe channels 260A through 260D (as shown with particularity channels260B and 260C). As will be appreciated by those skilled in the art, thenumber of such teeth 261 may be varied according to the needs of system200, taking into appropriate consideration overall system 200 weight,cost, fail-safe needs or the like, and that all such variants (i.e.,with or without teeth 261 formed in some or all of the channels 260Athrough 260D) are deemed to be within the scope of the presentinvention. Likewise, even though four channels 260A through 260D areshown in FIGS. 3C, 3D and 4C, the number of such channels may be greateror fewer, depending on the need; as with the use of teeth 261, all suchvariants in the number of channels are deemed to be within the scope ofthe present invention.

In the embodiment depicted in FIGS. 3C and 3D, two central channels260B, 260C are sized and shaped to cooperate with drive belts 255A thatfunction as primary load belts, while two outer channels 260A, 260Daccept fail-safe (also referred to as secondary load) belts 255B that donot carry a load during normal operation, but can do so upon failure ofone of the primary load belts 255A. As discussed above, the pulley 260embodiment of FIG. 4C has two of the channels 260B and 260C configuredto accept the drive belts 255A (and are also shown possessing teeth261), while channels 260A and 260D (presently shown without teeth) areconfigured to engage the fail-safe belt 255B; it will be appreciatedthat any combination of drive belts 255A and fail-safe belts 255B—aswell as a corresponding number of channels to engage them, and whethersuch channels are outfitted with teeth 261—is also deemed to be withinthe scope of the present invention. The combination of at least oneprimary load belt 255A and at least one secondary load belt 255B thattogether engages one of the pulleys 260 is referred to herein as a beltset (or more simply, set). As shown with particularity, the size andnumber of pulley channels 260A through 260D, as well as the number andsize of both drive belts 255A and fail-safe belts 255B that as a setcooperate with such channels, may be varied according to the needs ofthe particular crosshead drive system 200.

Both the drive belts 255A and the fail-safe belts 255B can be made fromthe same materials, while in another configuration, they can be madefrom different materials, depending on the end-use application andrelated design requirements. For example, the drive belts 255A mayinclude continuous fiber reinforcement to provide additionalload-carrying capability. Referring with particularity to FIG. 4B,details of one embodiment of the drive (i.e., primary load) belt 255Aconstruction is shown. In particular, drive belt 255A includeselongated, axially extending structural fibers 257 embedded in aflexible matrix or support 258. In one form, the material making up thefibers 257 imparts a high tensile strength and low stretching/elongationto the drive belt 255A; such material may be a carbon fiber-basedmaterial such as that found in U.S. Pat. No. 5,807,194 entitled TOOTHEDBELT the entirety of which is incorporated by reference herein.Likewise, the material making up the flexible support 258 can be arubber- or synthetic-based material, such as polyurethane or the like.Additional materials (not shown) may be used to improve environmentalresistance, handling, frictional resistance or the like. In a preferredform, the fibers 257 are continuous and extend for a substantialentirety of the length of the drive belt 255A as it extends from thecounterweight 265 to the crosshead 210. In a likewise preferred form,the cross-sectional profile of the drive belts 255A is generallyrectangular with the longer of its two lateral dimensions sized to fitwithin a comparable channel 260B, 260C or the like of pulley 260.Although the fibers 257 are presently shown as only being present in thebase (i.e., flat) portion of the support 258 of drive belt 255A, theymay also be present in the portion that corresponds to the teeth 256,and in such case may be made of discontinuous (i.e., chopped) fiberreinforcements. In another variant (not shown), the fibers 257 arepresent throughout a partial depth of the base portion of the support258 of drive belt 255A, while the teeth may or may not includeadditional reinforcement.

In one non-limiting form, the profile of teeth 256 of the belt 255(whether in the form of the primary load belt 255A or the secondary loadbelt 255B) can be generally trapezoidal in shape (including curvilinearvariants) with a belt thickness, tooth height and tooth-to-tooth spacingsuitable for the belt operational environment. In one non-limitingconfiguration suitable for use with the pulleys 260 that may be usedwith decoking system 1, the primary load belt 255A may include a roughly0.55 inch spacing between adjacent teeth that are about 0.25 inch tallas part of a belt maximum thickness of about 0.40 inch. The teeth 261 ofthe companion pulley 260 may be similarly shaped and sized to promotesecure engagement between them during belt-to-pulley meshing. The speedof the drive system is such that it imparts a relatively low rotationalspeed to the pulley 260; in one form, such speed is no more than about10 revolutions per minute (rpm) for a pulley 260 with a diameter ofbetween about 24 and about 36 inches. Likewise, the width of eachchannel 260A, 260B, 260C or 260D may be between about 1.5 and 2 inches.By using the non-metallic belts 255 of the present invention, theinventor believes that between about 2,000 and 4,000 pounds may bereduced from a 15,000 pound cutting train of the decoking system 1.Furthermore, this permits removal of winches and secondary safetyequipment (the latter of which often requires extensive periodicmaintenance) to further simplify the system 1.

By way of the four-channel variants shown in FIGS. 3C, 3D and 4C, two ofthe belts 255 may be of the primary load belt 255A variety; each wouldinclude substantially continuous carbon fiber reinforcement along thebelt longitudinal axis; as discussed above, these belts 255A willinclude teeth 256. Thus, each four-channel pulley 260 would include twoof these primary load belts 255A to engage the corresponding teeth 261to transfer the forces due to the cutting train load. The remaining twoof belts 255 would be the secondary load belt 255B that could define aflat or rectangular cross-sectional profile with no teeth. This belt255B, as well as the corresponding channel 260D, will remain as part ofthe fail-safe operation in the event one of the primary load belts 255Afail. Various material choices, dictated by cost, ease of manufacture,load-bearing abilities or the like, may be used; such materials mayinclude engineered plastics (such as with Dyneema® or related ultra highmolecular weight polyethylene fibers).

The system fail-safe characteristic may be achieved in different ways.For example, a sensor-based device (not shown) as part of a conditionmonitoring system may be included to continually monitor belt 255tension to look for evidence of wear; such a device may be coupled to aprocessor-based controller (not shown) that includes a comparitor,algorithm or other means for determining when belt 255 replacement isnecessary. In a related way, the condition of the driving belts 255A canpotentially be monitored using optical methods coupled with imageprocessing algorithms that are cooperative with such a controller. In amore particular form, once one of the belts 255 is determined to be inneed of replacement, it can be done while leaving the others in place.In another form, the fail-safe operation may be achieved by having oneor more secondary belts 255B configured to engage the pulley 260 in sucha way that the corresponding one or more of the channels 260A-260D ofthe pulley 260 are devoid of teeth or other belt-engaging enhancements,thereby making the cooperation between them based solely on frictionalcontact between their contacting surfaces. In other words, because theweight of the system 200 is always counterbalanced, the secondary loadbelts 255B only need to overcome inertia loads, making manipulation ofthe system 200 into a more favorable belt-replacement location simpler.In this configuration, the secondary load belt 255B remainssubstantially unloaded, over a flat pulley without carrying any loadduring normal raising and lowering operations of the system 200,decoking tool 10 and rotary joint 30, but capable of holding the fullload in its present position if the primary load belt part of system 200breaks. In such circumstance, a new primary load belt 255A may replacethe one that failed, while the secondary belt 255B is robust enough topermit some movement of the system 200 to a more convenient position tochange the effected belts.

The secondary load belt 255B (which is shown in cross-sectional profilein FIG. 3D) is preferably made from an engineered plastic material (suchas Dyneema® as mentioned above) in order to impart to it enhancedmechanical (for example, strength) properties. Such engineered plasticmay include a blend of various materials, including continuous ordiscontinuous fiber reinforcement; in the former configuration,secondary load belt 255B may generally resemble the primary load belt255A with its toothed features, although perhaps with a lighter fiberloading. In yet another form, such engineered materials may includethose with very small (i.e., nanotechnology-sized, for example, belowabout 10 nanometers in diameter) particles or related reinforcementmaterials. Likewise, in another form, these fail-safe secondary belts255B may be of similar construction as that of primary load belts 255A,or may be made of a simpler construction, such as by not including anyfiber reinforcement, maintaining a strictly flat (i.e., rectangularcross-sectional profile) shape, or the like.

Referring again with particularity to FIG. 4C in conjunction with FIG.4B, in one form, pulley 260 includes two side-by-side channels 260B and260C. Each belt 255 is about 1.75 inches wide; with teeth, eachtwo-channel pulley 260 may carry up to about 15,000 pounds of load(making the total rating for a two-pulley system about 30,000 pounds fora safety factor of about two for a notional 15,000 pound cutting train).Thus, if two of the four belts 255 are operational, an ongoing cuttingoperation may be completed before changing the belts. Even in situationswhere the two belts 255 that fail are on the same pulley 260, thesecondary load belt 255B will still keep the crosshead 210 leveled tomove it into a position where the broken belt can be replaced, as theactual load across the system 200 remains substantially weight-balanced.In another form, pulley 260 includes four side-by-side channels 260A,260B, 260C and 260D. Thus, if the six of the belts 255 (of a total ofeight belts for a two-pulley system) fail, the previously-dormant flatsecondary belt 255B will engage and hold the load. In such case, it maybe necessary to use a separate portable winch to slowly bring thecrosshead 210 up to where repair personnel can access it to connect onenew belt 255 in each pulley 260. The gearbox 224 may be equipped with aworm gear to avoid rotation with the force coming from the weight-drivenside. Using the exemplary form of FIG. 4C, if all three of the primaryload belts 255A in one side of the crosshead 210 are cut, the fail-safesecondary load belt 255B is strong enough to hold the load andconsequently keep the crosshead 210 leveled; this in turn allows theother three still-functioning primary load belts 255A on the oppositeside of the crosshead 210 to continue to move the crosshead 210 up anddown Likewise, if subsequently these other three drive belts in theother side collapse, the fail-safe secondary load belt 255B on that sidewill also hold the load in place. At this point, a service technicianhas a few repair options. First, some of the primary load belts 255A maybe replaced; as mentioned above, the load-bearing capacity of thesecondary load belts 255B along with the counterweight-based design ofthe system 200 permits the system 200 to be move to a position at whichthe broken primary load belts 255A may be replaced. Another option is tolift or lower the (still balanced) cutting train with temporary ropesuntil the crosshead 210 gets to a point in which the broken primary loadbelts 255A can be changed easily.

An additional cover 275 may be placed over the top of the pulleys 260 inorder to keep debris from collecting on them or belts 255. Such cover275 may also include an optically-transparent inspection window to allowquick visual assessment of the belts 255. Cover 275 may also includecutouts defined in its lower surface that are shaped to complement thatof the radially-outward edge of pulley 260 in order to keep the belts255 from jumping out of the channels 260A through 260D; this can be seenwith particularity in FIG. 3D. Even though the cover 275 is particularlywell-suited for configurations where the pulley 260 is toothed, it alsoworks with the other versions discussed herein as well.

Referring next to FIG. 5, an alternate configuration for a toothedversion of the pulley 260 and belt 255 of FIG. 4A is shown in aninverted form for clarity of view. In actual use, the drive belt 355would be situated above the pulley 360 such that instead of teeth (suchas teeth 256 of the belts 255, 255A of FIGS. 4A and 4B), it includescutouts 356 formed therein that would engage the teeth 361 of the pulley360 near the top in order to permit the belt 355 to fulfill itsweight-bearing function for the crosshead 210 and ancillary equipment.In a manner similar to pulley 260 with teeth 261, belt 355—which whilecontinuing to define a generally rectangular cross-sectional profile—nowincludes numerous apertures or cutouts 356 that are of a generally ovalor rectangular shape with the prolate axis oriented widthwise (i.e.,across the width W) on belt 355. The size of the cutouts 356 formedalong the length L is such that their dimensions could be generallysimilar to that of the teeth 361 that are formed on pulley 360,depending of the nature of the engineered material (an example of whichis Dyneema®, carbon fiber or the like) that is used for the belt 355. Inone form, these cutouts 356 may be lined with an additional wearresistant fabric-reinforcement, to achieve better edge distribution ofthe load. As such, of the two types of belts discussed herein (i.e., theload-bearing primary or drive belts and the secondary fail-safe belts),the first preferably include teeth or cutouts such that they can be usedwith toothed pulleys, while the second preferably defines a rectangularcross section without teeth or holes such that these latter belts act asa sling.

It is noted that terms like “preferably,” “commonly,” and “typically”are not utilized herein to limit the scope of the claimed invention orto imply that certain features are critical, essential, or evenimportant to the structure or function of the claimed invention. Rather,these terms are merely intended to highlight alternative or additionalfeatures that may or may not be utilized in a particular embodiment ofthe present invention Likewise, for the purposes of describing anddefining the present invention it is noted that the term “substantial”(and its variants) is utilized herein to represent the inherent degreeof uncertainty that may be attributed to any quantitative comparison,value, measurement, or other representation. The term is also utilizedherein to represent the degree by which a quantitative representationmay vary from a stated reference without resulting in a change in thebasic function of the subject matter at issue.

Having described the invention in detail and by reference to specificembodiments thereof, it will be apparent that modifications andvariations are possible without departing from the scope of theinvention defined in the appended claims. More specifically, althoughsome aspects of the present invention are identified herein as preferredor particularly advantageous, it is contemplated that the presentinvention is not necessarily limited to these preferred aspects of theinvention.

1. An apparatus for moving a coke cutting tool within a decoking drum,said apparatus comprising: a rigid member configured to extend asufficient height above said drum to permit a range of vertical movementof said cutting tool substantially therethrough; and a motorized systemconfigured to selectively raise and lower said cutting tool, said systemcomprising: a crosshead defining a connection to said cutting tool andmovably cooperative with said rigid member; a plurality of pulleyssecured to said rigid member, each configured to rotate about an axis; aplurality of non-metallic belts, each cooperative with rotationalmovement of a respective one of said pulleys and secured at one end tosaid crosshead; at least one counterweight secured to an opposing end ofa respective one of said belts; and at least one motor secured to saidrigid member, said at least one motor configured to impart rotationalmovement to said pulleys such that said belts selectively raise or lowersaid crosshead relative to said rigid member.
 2. The apparatus of claim1, wherein said pulleys consist of two said pulleys each configured torotate in a direction opposite of one another.
 3. The apparatus of claim1, wherein each of said pulleys defines a plurality of side-by-sidechannels each of which is sized to accept a corresponding one of saidbelts therein.
 4. The apparatus of claim 3, wherein at least one of saidchannels and corresponding ones of said belts define a plurality ofprotruding teeth to promote an enhancement to said cooperativerotational movement.
 5. The apparatus of claim 4, wherein said at leastone of said channels defines a plurality of protruding teeth andcorresponding ones of said belts defines a plurality of protruding teethsuch that upon rotational movement of said belt around said pulley, saidchannel protruding teeth and said belt protruding teeth mesh with oneanother.
 6. The apparatus of claim 4, wherein said at least one of saidchannels defines a plurality of protruding teeth and corresponding onesof said belts defines a plurality of apertures each of which are sizedto accept a corresponding one of said plurality of teeth.
 7. Theapparatus of claim 6, wherein said plurality of apertures arereinforced.
 8. The apparatus of claim 7, wherein said reinforcedapertures are fabric-reinforced.
 9. The apparatus of claim 3, whereinsaid belts that cooperate with a corresponding one of said pulleyscomprise at least one primary load belt and at least one secondary loadbelt.
 10. The apparatus of claim 9, wherein more of said channels withinsaid respective one of said pulleys engage said primary load belts thansaid secondary load belts.
 11. The apparatus of claim 9, wherein atleast one of said primary load belt and said secondary load beltcomprises a substantially continuous reinforcing fibers embeddedtherein.
 12. The apparatus of claim 9, wherein said primary load beltand a respective channel within said pulley define a plurality ofprotruding teeth to promote an enhancement to said cooperativerotational movement.
 13. The apparatus of claim 1, wherein at least oneof said belts comprises a carbon fiber reinforcement.
 14. The apparatusof claim 13, wherein said carbon fiber reinforcement comprises asubstantially continuous reinforcement along the dimension of said atleast one belt that is substantially coincident with tensile forcesimparted thereto by said crosshead and said counterweight.
 15. Adecoking assembly comprising: a decoking tool configured to receive acutting fluid from a high pressure fluid source; and an apparatus formoving a coke cutting tool within a decoking drum, said apparatuscomprising: a rigid member configured to extend a sufficient heightabove said drum to permit a range of vertical movement of said cuttingtool substantially therethrough; and a motorized system configured toselectively raise and lower said cutting tool, said system comprising: acrosshead defining a connection to said cutting tool and movablycooperative with said rigid member; a plurality of pulleys secured tosaid rigid member, each configured to rotate about an axis; a pluralityof non-metallic belts, each cooperative with rotational movement of arespective one of said pulleys and secured at one end to said crosshead;at least one counterweight secured to an opposing end of a respectiveone of said belts; and at least one motor secured to said rigid member,said at least one motor configured to impart rotational movement to saidpulleys such that said belts selectively raise or lower said crossheadrelative to said rigid member.
 16. The decoking assembly of claim 15,wherein each of said pulleys defines a plurality of side-by-sidechannels each of which is sized to accept a corresponding one of saidbelts therein.
 17. The decoking assembly of claim 16, wherein said beltscomprise at least one primary load belt and at least one secondary loadbelt such that each of said at least one primary load belts engages oneof said channels within said corresponding one of said pulleys and eachof said at least one secondary load belts engages another of saidchannels within said corresponding one of said pulleys.
 18. The decokingassembly of claim 15, wherein at least one of said belts comprises acarbon fiber reinforcement that is substantially continuous along thedimension of said at least one belt that is substantially coincidentwith tensile forces imparted thereto by said crosshead and saidcounterweight.
 19. A method of operating a portion of a decoking system,said method comprising: arranging an assembly to be adjacent a decokingdrum, said assembly comprising: a coke cutting tool configured toreceive a cutting fluid from a high pressure fluid source; and anapparatus for moving a coke cutting tool within a decoking drum, saidapparatus comprising: a rigid member configured to extend a sufficientheight above said drum to permit a range of vertical movement of saidcutting tool substantially therethrough; and a motorized systemconfigured to selectively raise and lower said cutting tool, said systemcomprising: a crosshead defining a connection to said cutting tool andmovably cooperative with said rigid member; a plurality of pulleyssecured to said rigid member, each configured to rotate about an axis; aplurality of non-metallic belts, each cooperative with rotationalmovement of a respective one of said pulleys and secured at one end tosaid crosshead; at least one counterweight secured to an opposing end ofa respective one of said belts; and at least one motor secured to saidrigid member, said at least one motor configured to impart rotationalmovement to said pulleys such that said belts selectively raise or lowersaid crosshead relative to said rigid member; and using said motorizedsystem to selectively raise and lower at least said crosshead and saidcoke cutting tool relative to said decoking drum and said rigid member.20. The method of claim 19, wherein each of said pulleys defines aplurality of side-by-side channels each of which is sized to accept acorresponding one of said belts therein.
 21. (canceled)
 22. (canceled)23. (canceled)
 24. (canceled)
 25. (canceled)